1. Field of the Invention
The present invention relates to a configuration of a surface-mounted module.
2. Description of Background Arts
FIG. 1 is a perspective view of a conventional surface-mounted module 111. Module 111 is a high-frequency circuit such as a high-frequency, high-output amplifier. On multi-layer substrate 6 of module 111, a circuit element 7 and a circuit element 8, which are units of individual functions, are mounted. Circuit element 7 and circuit element 8 include chip parts 3 and wiring 4. Chip parts 3 and wiring 4 are connected to wiring inside the layer or an LCR element through a via hole 5.
Next description will be made on connections between module 111 and a base substrate 2. Module 111 is mounted on the surface of base substrate 2 by soldering such as reflow, or other methods. FIG. 2 is a diagram showing the configuration of the rear surface of module 111 (FIG. 1). As clear from the diagram, module 111 (FIG. 1) has a plurality of electrodes 9 and a comparatively large grounding electrode 10 on the rear surface. It is connected to module 111 and wiring 4 (FIG. 1) on base substrate 2 via a plurality of electrodes 9 disposed at four corners of module 111 rear surface. The other grounding electrode 10 is connected to grounding wiring 40 (FIG. 1) on base substrate 2 by soldering, etc. Grounding electrode 10 occupies nearly the remainder of the area except electrode 9, and this configuration can thereby achieve satisfactory heat radiating characteristics and high-frequency characteristics.
Referring now again to FIG. 1, circuit element 7 and circuit element 8 of module 111 are constructed by electrically connecting them to the inside or the surface of module 111. Because the characteristics of each of circuit elements 7, 8 vary, evaluating, sorting out, and adjusting the radio frequency (RF) characteristics for each circuit element when module 111 is manufactured can improve the yield of module 111.
However, as shown in FIG. 1, when circuit elements 7 and 8 are mounted on module 111, circuit elements cannot be evaluated individually. Consequently, the process yield of the whole module 111 is poor and a high manufacturing cost results.
It is an object of the present invention to enable the evaluation of each module circuit element even after the module is assembled. It is another object of the present invention to enable the evaluation of the whole module mounted on the substrate.
The module according to the present invention includes a module substrate; and a plurality of circuit elements formed on the module substrate and insulated from one another, each circuit element being equipped with an independent function, wherein the module achieves a specified function by operating the each circuit element, and wherein the each circuit element has a terminal insulated from terminals of other circuit elements on a surface of the module substrate. According to this configuration, the high-frequency characteristics, etc. of each circuit element can be evaluated individually even after the module is formed. Sorting and adjusting each one of the circuit elements using the evaluation results enables the high-yield manufacture of modules. Consequently, the module manufacturing cost can be reduced.
The surface-mounted module according to the present invention includes a module that has a module substrate and a plurality of circuit elements formed on the module substrate and being insulated one another, each circuit element being equipped with an independent function and having a terminal insulated from terminals of other circuit elements on a surface of the module substrate; and a base substrate that supplies electric power to the module and has a connection wiring to electrically connect terminals of at least two of the plurality of circuit elements on the surface of the module substrate, wherein the surface-mounted module achieves a specified function by operating the each circuit element according to the power supplied from the base substrate via the connection wiring. According to this configuration, each circuit element connected via connection wiring can be operated in accordance with the electric power supplied from the base substrate and the specified functions can be achieved.
The terminals may be formed on a first surface opposite to a second surface of the module substrate provided with the circuit element. Therefore, the area of the top layer of the module to which a large number of chip parts, etc. are to be mounted can be secured and a high degree of design freedom can be secured. The module may further includes a grounding electrode which grounds the each circuit element. The base substrate further includes a grounding wiring that connects and grounds the grounding electrode of the module and that surrounds the connection wiring. The connection wiring and the grounding electrode form a coplanar-type line. The module may further include a first grounding electrode which grounds the each circuit element. The base substrate may further include a second grounding electrode that connects and grounds the first grounding electrode. The connecting wiring and the grounding electrode form a slot-type line. In addition, the first grounding electrode of the module may surround the terminals. Alternatively, the first grounding electrode of the module may be disposed around the first surface.
Accordingly, the electric field can be confined between the grounding wiring and connection wiring and it could be free of influences of the lower layer of base substrate or the top layer of module substrate. Consequently, it becomes possible to connect circuit elements without impairing the high-frequency characteristics.
Another surface-mounted module according to the present invention includes a module that has: a module substrate; a plurality of circuit elements formed on the module substrate and being insulated one another, each circuit element being equipped with an independent function and having a terminal being formed on a first surface opposite to a second surface of the module substrate provided with the circuit element, said terminal electrically connecting to the circuit element by conductor; and a grounding electrode which grounds the each circuit element. The surface-mounted module further has a base substrate that connects and grounds the grounding electrode of the module and that supplies electric power to the module. The surface-mounted module achieves a specified function by operating the each circuit element according to the power supplied from the base substrate via a connection wiring. The first surface has a third surface at the position recessed from the outer circumferential position of the first surface, and the terminal is formed on the third surface. Because the terminal is kept away from the base substrate in a predetermined distance, the terminal is less susceptible to the base substrate. These are connected by conductors (for example, conductive wire, conductive chip, or metal).
The third surface is potted so as to cover the conductor. By this potting, the conductors are fixed and at the same time, solder rises to the terminals and prevents the terminals from shorting when the module and the base substrate are reflowed.
The grounding electrode may be formed on the third surface. The grounding electrode of the module will be formed at the recess to which the terminals of the circuit elements are installed. Accordingly, a signal needle and a grounding needle of a probe needle can be brought in contact to the module terminal and the grounding electrode located comparatively close and high-frequency characteristics of each circuit element can be individually evaluated.
The conductor may be at least one of conductive wire, conductive chip, and metal.
The terminal may be formed on the second surface of the module substrate. Therefore, the module can adopt a so-called flip-chip configuration for the base substrate and no connection path (via hole) is required from the surface on the circuit element side to the surface opposite to it, and the manufacturing cost can be reduced.